1. Anthropogenic Forcing of Ocean Warming and Its Effects on the West Antarctic Ice Sheet Theresa Diehl Physical Climatology Fall 2005

2. Earth’s Energy Imbalance Global net energy surplus of 1 W/m 2 Q. Where does all this energy go? A. ~85% in the last 40 years has gone toward warming the Earth’s oceans

3. Ocean Warming 1960-2000 Barnett et al., 2005

4. Three Possible Causes 1.Natural variability of the air-ocean system 2.External forcing due to solar or volcanic variability 3.Anthropogenic forcing from global warming (greenhouse gas and aerosol emissions)

5. Model Results for Natural Variability Barnett et al., 2005

6. Model Results for Human Forcing Barnett et al., 2005

7. Antarctica Oppenheimer, 2005

8. Schematic Cross-section Oppenheimer, 2005

9. In 1998, Oppenheimer… Noted that the Larsen and Wordie ice shelves were shrinking Hypothesized: Due to ice shelf basal melting? Rejects: Fast retreat of grounding lines when ice shelf is disrupted Predicts: Collapse of WAIS realistically within next 700 years, as early as 200 years, with 60-120cm of sea level rise possible this century just from WAIS

10. Jan 31, 2002 – March 7, 2002 http://nsidc.org/iceshelves/larsenb2002/animation.html

11. What about the other ice shelves?

12. What’s causing the thinning? Shepherd et al., 2004

13. Modeling the Observations for PIG Payne et al., 2004

14. Will this destabilize the ice sheet? Lythe et al., 2004 BEDMAP

15. Thank you